Vestibulospinal reflexes. X. Theoretical and clinical aspects of the stepping test

Test-re-test reliability and dynamics of the Fukuda–Unterberger stepping test

Background

The Fukuda-stepping-test (FST), i.e., repetitive walking on the spot while blindfolded, has been proposed as a means to assess the integrity of the vestibular pathways. While its sensitivity to detect abnormalities in patients is limited, it may be useful in studying the physiology of the subjective-straight-ahead (SSA). Considering reported systematic shifts in SSA in humans, we hypothesize that such asymmetries arise from individual differences in the orientation/configuration of the macular organs and in central processing of vestibular input. We hypothesize that such asymmetries are stable over time in individual subjects. Alternatively, such asymmetries may arise from random noise in the sensory/motor systems involved, demonstrating low reproducibility over time.

Materials and methods

Twenty-four subjects walked on the spot over 60 s while blindfolded (n = 6 trials per subject). Using an inertial measurement unit (IMU) placed at the chest, angular deviations were recorded and compared to manually-measured final positions. Both static (direction, magnitude) and dynamic (time-to-onset of deviation, pattern of deviations) parameters were retrieved from the yaw slopes.

Results

Significant deviations were found in 15/24 participants for the manual measurements (leftwards = 8; rightwards = 7), whereas when using the IMU-sensor 13/24 participants showed significant shifts (leftwards = 9; rightwards = 4). There was a high correlation (0.98) between manually measured rotation angles (average absolute deviations = 58.0 deg ± 48.6 deg; intra-individual variability = 39 deg ± 24 deg) and sensor-based yaw slopes (1.00 deg/s ± 0.88 deg/s; 0.67 deg/s ± 0.41 deg/s). Relevant yaw deviation was detected 22.1 s ± 12.3 s (range = 5.6 s-59.2 s) after the onset of marching (no relevant yaw-deviation in 15/139 measurements), showing a mostly linear behavior over time.

Conclusion

We observed significant inter-individual variability in task performance in the FST, reproducing findings from previous studies. With test-re-test reliability being moderate only, but at the same time observing a preference in the side of shifts in most trials and subjects, we conclude that likely both individually varying estimates of straight-ahead and random noise contribute to the pattern of angular deviations observed. Using an IMU-sensory based approach, additional dynamic parameters could be retrieved, emphasizing the value of such a quantitative approach over manual measurements. Such an approach may provide useful additional information to distinguish patients from healthy controls.

The Fukuda Stepping Test Is Influenced by a Concurrent Cognitive Task and Step Height in Healthy Young Adults: A Descriptive Study

Purpose: The Fukuda stepping test assesses spatial orientation in people with vestibular disorders. To standardize the test, it is important to know which factors influence the outcome. This study investigated the impact of two factors, a concurrent cognitive task and step height, on the Fukuda stepping test in healthy individuals. Method: A total of 16 young adults participated and completed 20 trials of the 50-step Fukuda stepping test in four conditions: comfortable and high step height and with and without a cognitive task. Body kinematics were collected using the three-dimensional motion analysis Vicon system. The cognitive task was to listen to a sequence of three-digit numbers and identify the total number of times that one pre-determined digit was presented. Results: All participants slowly turned and drifted forward during the test. The concurrent cognitive task yielded significantly shorter forward displacement and lateral deviation and lower stepping height, and high stepping produced significantly greater body rotation and lateral deviation. Conclusions: Performance on the Fukuda stepping test in healthy young individuals is influenced by a concurrent cognitive task and by step height. Clinicians and researchers must instruct people to use a comfortable step height during the test, and they must be aware that a concurrent cognitive task may improve test performance, at least among young adults.

Preventing Episodic Migraine With Caloric Vestibular Stimulation: A Randomized Controlled Trial

OBJECTIVE

To evaluate the safety and efficacy of a novel solid-state, caloric vestibular stimulation (CVS) device to provide adjuvant therapy for the prevention of episodic migraine in adult migraineurs.

BACKGROUND

Migraine causes significant disability in ∼12% of the world population. No current migraine preventive treatment provides full clinical relief, and many exhibit high rates of discontinuation due to adverse events. Thus, new therapeutic options are needed. CVS may be an effective and safe adjuvant-therapy for the prevention of episodic migraine.

METHODS

In a multicenter, parallel-arm, block-randomized, placebo-controlled clinical trial (clinicaltrials.gov: NCT01899040), subjects completed a 3-month treatment with the TNM™ device for CVS (refer to Fig. 2 for patient enrollment and allocation). The primary endpoint was the change in monthly migraine days from baseline to the third treatment month. Secondary endpoints were 50% responder rates, change in prescription analgesic usage and difference in total subjective headache-related pain scores. Device safety assessments included evaluation of any impact on mood, cognition, or balance.

RESULTS

Per-protocol, active-arm subjects showed immediate and continued steady declines in migraine frequency over the treatment period. After 3 months of treatment, active-arm subjects exhibited significantly fewer migraine days (-3.9 ± 0.6 from a baseline burden of 7.7 ± 0.5 migraine days). These improvements were significantly greater than those observed in control subjects (-1.1 ± 0.6 from a baseline burden = 6.9 ± 0.7 migraine days) and represented a therapeutic gain of -2.8 migraine days, CI = -0.9 to -4.7, P = .012. Active arm subjects also reported greater reductions in acute medication usage and monthly pain scores compared to controls. No adverse effects on mood, cognition, or balance were reported. Subjects completed the trial with an average rate of 90% treatment adherence. No serious or unexpected adverse events were recorded. The rate of expected adverse events was similar across the active and the placebo groups, and evaluation confirmed that subject blinding remained intact.

CONCLUSION

The TNM™ device for CVS appears to provide a clinically efficacious and highly tolerable adjuvant therapy for the prevention of episodic migraine.

Fukuda and Babinski-Weil tests: within-subject variability and test-retest reliability in nondisabled adults

The Fukuda Stepping Test and the Babinski-Weil test are clinical assessments that presumably reveal unilateral vestibular hypofunction. However, abnormal performances on both of these two tests have been found in nondisabled individuals. This study compared measures of lateral and longitudinal displacements and body rotation for both tests, as well as the within-subject variability and test-retest reliability of the measures. In addition, correlations between hand and foot dominance and these measures were studied. Fifty young, nondisabled participants performed three trials of the 100-step Fukuda test and three trials of the Babinski-Weil test. The testing session was repeated 7 d later (retest). Lateral displacement, body rotation, and within-subject variability of these two measures were larger on the Fukuda than the Babinski-Weil test. No difference in test-retest reliability was found between the two tests, and a significant correlation was found between body rotation on the Fukuda test and score on the Waterloo Footedness Questionnaire. There may have been smaller variability in results of the Babinski-Weil test because it contains fewer steps (36) than the 100-step Fukuda test. Future research should compare tests with an equal number of steps; but, in the meantime, the Babinski-Weil test seems to have better psychometric properties than the Fukuda test, at least in nondisabled individuals.

The efficiency of the sideways stepping test in detecting unilateral vestibular hypofunction

[Purpose] This study investigated to determine whether the Sideways Stepping Test (SST) is a useful test to detect unilateral vestibular hypofunction (UVH). [Subjects and Methods] Twenty-eight subjects including both male and females between the ages of 25 and 55 who had been diagnosed with UVH were recruited for the study. All the subjects were tested with the SST and followed by the head-shaking nystagmus (HSN) test using video electronystagmography (VENG) to confirm the presence of UVH. The results of both tests were then compared with each other to determine the correlation, sensitivity, and specificity. [Results] The results showed that the SST is strongly correlated with the gold standard HSN test using VENG and is highly sensitive and specific. [Conclusion] The present study showed that the SST is a highly valid test that can be used as an alternative method to the gold standard HSN test using VENG in detecting UVH.

What are the factors responsible for the deviation in stepping on the spot?

Without vision, keeping a straight-ahead direction while stepping on the spot is almost impossible, everybody deviates more or less. Several explanations for this, such as laterality, vestibulo-spinal influence, dopamine system, have been proposed. The aims of the experiment presented here were (1) to quantify the lateral deviation when stepping using a modified Fukuda test apparatus, and (2) to determine the factors potentially underlying such deviation. Twenty-five young adults, blindfolded, performed the experiment which consisted in stepping while holding a rotating vertical roll bar fixed on the wall. Four experimental conditions (i.e., normal, with an imposed pace, dual-task, or with the neck bent) were tested. All participants deviated towards one side or the other in all conditions. Adding an attentional load or imposing a particular pace did not change the amount of deviation. For three conditions (normal, with an imposed pace and dual-task), the deviation towards one side was not significantly larger than towards the other side at the group level. In the bent-neck condition, the deviation was significantly larger than in the other conditions. Furthermore, in this condition the deviation towards the left was significantly larger than the deviation towards the right at the group level. We discussed the results regarding the role of vestibular information and proprioceptive feedback from neck muscles in correcting a spontaneous deviation. Our results, however, go against the idea that sensorimotor lateral preferences are among the factors underlying such deviations, since we found no relationship between lateral preferences (hand, foot, and eye) and the side of deviation.

Falls among healthy, community-dwelling, older women: a prospective study of frequency, circumstances, consequences and prediction accuracy

OBJECTIVE

Most studies of falls among older people have focused on those with some degree of balance or mobility impairment. This study aimed to establish whether falls and associated injuries were a major problem among healthy, older women, whether there were some common features in the falls, and whether these falls could be accurately predicted.

METHOD

Ninety-six healthy, active community-dwelling women in Melbourne, Australia, aged at least 70 years (mean 74.1 +/- 4.0) were initially measured on a comprehensive series of laboratory and clinical balance tests, gait, strength and psychometric measures. Subjects were monitored for falls events, circumstances and consequences by use of falls diaries and monthly phone calls. Baseline measures of clinical balance measures and gait were comparable to other studies reporting scores on these measures in samples of healthy older people.

RESULTS

During the 12-month follow-up period, 49% of subjects fell, with 23% falling more than once; 9% suffered fractures as a result of their fall and 10% suffered strains or other moderate injuries. Many of the falls occurred during non-threatening activities such as walking, often under altered sensory or environmental conditions. Multivariate logistic regression identified gait symmetry and gait double support duration as the variables most strongly associated with prediction of multiple fallers.

CONCLUSIONS

The results highlight that falls are a major problem among healthy active older women, and that targeted falls prevention programs are required for this group.

Fear of falling revisited

OBJECTIVE

To evaluate the measurement properties of an expanded version of the Falls Efficacy Scale (FES)-a measure of fear of falling. The original FES measures fear on almost exclusively indoor activities, which may limit the usefulness of the scale in identifying early stages of fear of falling in active community-dwelling older people.

DESIGN

Two-group convenience sample.

SETTING

An outpatient referral clinic, and community-dwelling older people recruited from various sources.

SUBJECTS

A volunteer sample of 111 healthy community-dwelling elderly (mean age 74.0 years) and a sample of 68 older people referred to a Falls and Balance Clinic (FBC) (mean age 79.2). Twenty-one subjects (9 healthy elderly and 12 FBC patients) were tested twice 1 week apart to investigate retest reliability.

MAIN OUTCOME MEASURES

A 14-activity questionnaire (the Modified Falls Efficacy Scale [MFES]) was used that incorporated the original 10-activity FES and four additional activities. Falls efficacy was rated on a 10-point visual analogue scale for each activity.

RESULTS AND CONCLUSIONS

The MFES demonstrated high internal consistency (Cronbach's alpha.95) and less skew than the original FES (-2.4 and -3.3, respectively). Factor analysis of the MFES revealed two factors accounting for 75% of the sample variance, grouping into an "indoor type activity" factor and an "outdoor type activity" factor. Retest reliability for the MFES was high (intraclass correlation coefficients = .93). Significant differences were evident between the FBC group and the healthy older group on all items of the MFES and on the total MFES score (p < .05). On the basis of these preliminary findings, the MFES appears to be a reliable and valid measure of falls self-efficacy, and could be a useful addition in the comprehensive assessment of older people with balance disturbance or falls.